The productive potential of the permanent grasslands varies depending on technological factors, station factors (altitude, supplying status with mineral elements etc.), floristic composition, and management (especially fertilization) (Porqueddu et al., 2004). The main goal of this paper is to find the dependence of the green mass production on the nitrogen amount applied in the grassland of Vârciorova and to determine the production increase obtained for 1 kg nitrogen active substance in the studied variants. In order to achieve the established objective, among the experiments with chemical fertilizers studied for five years (2006-2010), we selected only those variants where different amounts of nitrogen were applied (without phosphorous and potassium): V2 (N 100 P 0 K 0 ), V3 (N 200 P 0 K 0 ) and V8 (N 100+100 P 0 K 0 ). The effect of nitrogen is more pronounced after its application for a long time period. Of course, to these findings a multitude of other factors contributes also, for example, the abundant precipitations from this area which favour the nitrogen consume by plants. The achieved results showed that production increase for 1 kg nitrogen active substance is higher at the dose of 100 kg/ha (23,66 kg green mass), than for the dose of 200 kg/ha (16,2 kg green mass, respectively 16,46 kg green mass), when nitrogen is applied for three years consecutively. The same situation persists also when nitrogen is applied five years consecutively, but the increases are larger.

green mass production, nitrogen fertilization, increase for 1 kg nitrogen active substance

Presentation: oral